Circuit 129
Your car

Fuses

Three boxes. One of them is why the radio is dark.

Photograph the card in your lid — numbering drifted, and lettered slots A–F are named on that card, not always on the plastic. Maps below are the common 1992–1998 R129 layout. Radio is fuse 9 plus letter A, not a 16 A red named B.

Engine bayTrunkBattery
18A28A38A416A58A68A78A88A98A1116A128A138A148A158A168AA8AB8AC8AD16AE / F25A

Tap a slot. Colours: white 8 A, red 16 A, blue 25 A, green 30 A.

Engine-bay fuse & relay module

Fuse A · 8 A white

Radio

Letter A on the lid card is Radio — not B. Same coffin as 1–16, usually the lettered row; the letter is on the paper card, often not on the plastic. Empty if your card never listed it. Typical 8 A white ceramic. Do not hunt for a 16 A red here. Lid print wins over this map.

radioradio no powerradio deadno radiohead unit
Where
Under the hood, driver’s side on LHD cars (left, near the bulkhead / washer bottle). Black ‘coffin’ with a hinged lid. The fuse card lives in that lid — photograph it; numbering drifted across the years.
How to open
Open the lid toward the wing. Numbered slots 1–16 are the two obvious rows. Lettered slots A–F (sometimes G/H) sit in the same coffin — usually a third row or the inner edge — and are named on the paper card, often not moulded in the plastic. Empty lettered slots are normal (no CD, no seat heat, no aux heater). Relays click in behind a second cover. A few maxi / high-current fuses hide under a black module toward the firewall.
Notes
Original Mercedes GBC ceramic fuses: white 8 A, red 16 A, blue 25 A, green 30 A. Aftermarket ATC / mini blades use a different colour code (red = 10 A, blue = 15 A) and have no 16 A size — a re-fused box will not contain a ‘red 16 A’. Water in the lid gasket corrodes the tracks. If a fuse looks good but the circuit is dead, pull it and check the copper rails.